import os
def split_relation_subtable(data, save_dir):
    """拆分卷烟商户特征相关性子表"""
    data['group_key'] = data["product_feat"].str.extract(r'^([^(]+)')
    grouped = data.groupby('group_key')
    sub_tables = {
        name: group.drop(columns=['group_key']).sort_values('relation', ascending=False)
        for name, group in grouped
    }
    
    for name, sub_data in sub_tables.items():
        sub_data.to_csv(os.path.join(save_dir, f"{name}.csv"), index=False)